Donald Rumsfeld Rumseld is also coming under criticism for failing to protect US soldiers inside their military bases in Iraq. Military investigators said Wednesday they believe a suicide bomber set off the explosion inside the military base in Mosul that killed 22 people including 18 Americans. The explosion went off inside a mess hall tent during lunchtime. . The military is still investigating how the attacker gained access to the base. The group, Ansar al-Sunna, claimed the attack was carried out by bomber was a local Iraqi resident that worked for months inside. However, military contractor Halliburton denied any local Iraqis worked at the base. This marks the first time a suicide bomber managed to infiltrate a US military base in Iraq.